1. Field of the Disclosure
The present technology relates to oil and gas production. In particular, the present technology relates to the in-situ replacement of fluids within well tools used in subterranean wells.
2. Description of the Related Art
In many wells, the pressure within the well is sufficient that producing oil and gas from the well requires only the installation of a production tree, and the opening of valves on the tree to allow the oil and gas to flow out of the well. In some instances, however, the pressure in the well is not sufficient to produce the oil and gas at acceptable rates. In such circumstances, it can be necessary to add an artificial lift mechanism, such as an electrical submersible pump (ESP), to help lift the oil and gas from the well. Furthermore, in some circumstances, a well that initially has sufficient pressure to produce without artificial lift may experience a decrease in well pressure, thereby arriving at a point where artificial lift is required.
A motor, pump, and protector, coupled together to make up the basic electrical submersible pump system. Motors are filled with dielectric fluid to provide lubrication to bearings and to provide a means to transfer heat away from the motor. The protector provides a reservoir for the oil volume expansion due to changes in temperature. In current electrical submersible pump systems, although there is some slight leakage of the motor oil through rotary seals in the protector, the motor oil can be considered a closed system in that motor oil is unable to be replaced downhole. Over the life of the electrical submersible pump, which can be several years, the motor oil is not replaced. The motor oil can degrade in place due to temperature and/or contaminants caused by motor wear. There is no maintenance performed on these electrical submersible pumps while they are in service.
In addition to electrical submersible pumps, there are of other downhole tools used for hydrocarbon development or production operation that include motors or other components that utilize fluids for actuation, cooling, lubrication, or other known uses.